title: Effects of lycobetaine on chromatin structure and activity of murine hepatoma cells.
abstract: The effects of lycobetaine (LBT) on DNA single strand break and chromatin conformation were examined by in-situ nick translation method. It was found that LBT did not cause DNA single strand break. After 2-h incubation of murine hepatoma cells with 1-50 micrograms/ml LBT in vitro, the chromatin transcription activity was inhibited gradually. This effect was time- and dose-dependent. Actinomycin D produced a similar effect; 10-hydroxycamptothecin not only caused DNA single strand break, but also altered chromatin conformation; homoharringtonine had no marked influence on either. By molecular hybridization technique, it was found that the effect of LBT on individual genes was somewhat different. After 2-h incubation of the cells with LBT, the sensitivities of c-myc, N-ras, and beta 2-microglobulin genes to DNase I were decreased from 75 +/- 6, 66 +/- 4, 70 +/- 8% to 28 +/- 8, 25 +/- 5, 28 +/- 7%, respectively, while that of c-myb and beta-globin genes (8 + 6%, 6 + 5%) did not change obviously.
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: S L
authors.initials: SL
authors.lastname: Yang
authors.forename: B
authors.initials: B
authors.lastname: Xu
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D047151:Amaryllidaceae Alkaloids; D000818:Animals; D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D002166:Camptothecin / Q000031:analogs & derivatives / Q000494:pharmacology; D002843:Chromatin / Q000187:drug effects*; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000187:drug effects; D003609:Dactinomycin / Q000494:pharmacology; D006248:Harringtonines / Q000494:pharmacology; D000077863:Homoharringtonine; D007212:Indolizines; D008114:Liver Neoplasms, Experimental / Q000473:pathology; D051379:Mice; D009857:Oncogenes / Q000187:drug effects*; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D000470:Alkaloids; D047151:Amaryllidaceae Alkaloids; D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D002843:Chromatin; D004273:DNA, Neoplasm; D006248:Harringtonines; D007212:Indolizines; D003609:Dactinomycin; C016175:ungeremine; D000077863:Homoharringtonine; C028098:10-hydroxycamptothecin; D002166:Camptothecin